Unless in Scala

In Scala, the unless keyword is not a built-in construct of the language. However, it can be created using a combination of the if and ! (logical NOT) operators.

Here's an example of using unless in Scala:

val x = 10
if (!(x % 2 == 0)) {

  println("x is odd")

}
// The above code is equivalent to:

unless (x % 2 == 0) {

  println("x is odd")

}

In this example, we first check if x is odd using the % (modulo) operator to get the remainder when x is divided by 2, and then negate the result using the ! operator. If the expression is true (i.e., x is odd), we print a message to the console.

The unless statement in the second half of the code has the same effect as the if statement, except that it reads more naturally. However, this requires defining the unless function as follows:

def unless(condition: => Boolean)(codeBlock: => Unit) = {
  if (!condition) codeBlock
}

With this code, you can use unless as a regular function that takes a condition and a code block.